如何让csv阅读器忽略大括号中的逗号(花括号、正方形和角度)？

Question

我有逗号分隔的值，其中包含嵌套大括号中的逗号。具体地说，我将输入逗号分隔的C++11对象。

例如，以下是一个输入：

std::vector<int>{32, 45, 10}, std::array<std::string, 5>{"a", "bc", "def", "ghij", "whoa, this is, a toughie"}, 8, "foo, bar", {"initializer-list?", "no problem!", "(hopefully...)"}

下面是我想要的输出：

[
    'std::vector<int>{32, 45, 10}',
    'std::array<std::string, 5>{"a", "bc", "def", "ghij", "whoa, this is, a toughie"}',
    '8',
    'foo, bar',
    '{"initializer-list?", "no problem!", "(hopefully...)"}'
]

但是python的csv给了我：

[
    'std::vector<int>{32',
    '45',
    '10}',
    'std::array<std::string',
    '5>{"a"',
    '"bc"',
    '"def"',
    '"ghij"',
    '"whoa',
    'this is',
    'a toughie"}',
    '8',
    'foo, bar', # at least this one works :/
    '{"initializer-list?"',
    '"no problem!"',
    '"(hopefully...)"}'
]

如何自定义csv模块来处理这些情况？

Answer 1

您可以使用正则表达式来拆分每一行，然后对其进行清理

import re
a = r'std::vector<int>{32, 45, 10}, std::array<std::string, 5>{"a", "bc", "def", "ghij", "whoa, this is, a toughie"}, 8, "foo, bar", {"initializer-list?", "no     problem!", "(hopefully...)"}'

# split on occurrences of "}, s"
results = re.split('},\s+s', a)

注意：拆分将从每个字符串的末尾删除} (最后一个字符串除外)，并从除第一个字符串以外的每个字符串中删除s。

编辑：

我想尝试解决这个问题，并提出了以下建议(假设字符串不包含集合{,},",<,>中的单个字符)。您可以通过提前查看cpp声明来更具体地删除<,>案例。

a = r'std::vector<int>{32, 45, 10}, std::array<std::string, 5>{"a", "bc", "def", "ghij", "whoa, this is, a toughie"}, 8, "foo, bar", {"initializer-list?", "no problem!", "(hopefully...)"}'

l_braces = {"{", "<"}
r_braces = {"}", ">"}

def split(s):
  brace_count = 0
  quote_count = 0
  breaks = []

  for i, c in enumerate(s):

    if c == '"':
      quote_count += 1
      if quote_count % 2 == 1:
        brace_count += 1
      else:
        brace_count -= 1

    if (c in l_braces):
      brace_count += 1

    if (c in r_braces):
      brace_count -= 1

    if (c == ",") and (brace_count == 0):
      breaks.append(i)

  pieces = []

  lag = 0
  for b in breaks:
    pieces.append(s[lag:b].strip())
    lag = b+1

  pieces.append(s[breaks[-1]+1:].strip())
  return pieces

print(split(a))

其中print(split(a))将打印以下内容...

['std::vector<int>{32, 45, 10}',
 'std::array<std::string, 5>{"a", "bc", "def", "ghij", "whoa, this is, a toughie"}',
 '8',
 '"foo, bar"',
 '{"initializer-list?", "no problem!", "(hopefully...)"}']

Answer 2

当CSV模块找到一个逗号时，它只是分隔值。它不关心其他符号。

为了达到你想要的效果，你必须扩展模块逻辑，让它能够检测到像"{“这样的开括号。当它找到一个左方括号时，所有逗号都应该被忽略，直到找到一个右方括号。

这样，您应该可以获得所需的输出。